Piezoelectric vibrators especially quartz crystal vibrators for electronic watches should be made small in size and must work with small power consumption.
Conventionally quartz crystal vibrators of this kind are made by photo etching techniques. There are some defects resulting from photo etching such as high equivalent resistance resulting from distortion which accrues during the etching treatment and weak adherence of film electrodes and masses for frequency adjustment which are deposited on the surface of the vibrator. The resonant frequency of such vibrators is adjusted by removing a portion of the metal mass by laser evaporation. Since evaporated metal particles are apt to adhere on the surface of the vibrator again, the resonant frequency of the vibrator is apt to shift when such metal particles are subsequently dislodged by shock.